The 2024 Senate race is kicking off with several sitting Democrats revealing whether they will seek another term, or retire and leave their seat vulnerable for a red flip.

Democrats have to defend 23 seats next cycle, more than twice the amount of Republicans who are seeking to hold 10 Senate seats.

Keep reading to see who is in, who is out, and who remains undecided in the 2024 Democratic race for Senate majority.

Who's in?

Sen. Sherrod Brown, D-Ohio., was the first vulnerable Senator to announce he would be seeking a fourth term in the Senate. Brown is considered to be in a vulnerable position, as voters in the Buckeye State are beginning to trend right.

Sherrod Brown at debate

Senator Sherrod Brown announced in November his decision to seek re-election. (Phil Long)

In the 2016 presidential election, former President Donald Trump won Ohio against former Secretary of State Hillary Clinton by about 8 percentage points. Trump also defeated President Joe Biden in Ohio in the 2020 election by the same margin, 53% to 45%.

Sen. John Tester, D-Mont., announced Wednesday he will seek another term in Montana, but faces a tough re-election in the overwhelmingly red state.  

JOE MANCHIN ‘NOT RUNNING’ FOR PRESIDENT, CONSIDERS POLITICAL FUTURE AS POTENTIAL GOP CHALLENGERS LOOM

Who's out?

The office of Sen. Dianne Feinstein, D-Calif., who is 89 years old, announced a couple weeks ago that she will not be seeking re-election in 2024.

Democrats are already lining up for the open seat, including Reps. Adam Schiff, D-Calif., Barbara Lee, D-Calif., and Katie Porter, D-Calif.

California Sen. Dianne Feinstein will not seek re-election

Sen. Dianne Feinstein, D-Calif., will not seek another term in 2024. (J. Scott Applewhite)

In Michigan, Sen. Debbie Stabenow, D-Mich., also decided not to seek another term after holding the position for two decades. "Inspired by a new generation of leaders, I have decided to pass the torch in the U.S. Senate," she said in her retirement announcement.

Rep. Elissa Slotkin, D-Mich., has her eyes on the open seat, officially announcing her Senate campaign on Monday.

Montana Senator Steve Daines, National Republican Senatorial Committee (NRSC) Chair who will be leading the charge to oust Democratic Senators next cycle, recently said that he expects more Democratic retirements as 2024 approaches. "I think each Democratic senator who decides to run knows to run away from Joe Biden. So I think there's a movement here of retirements. They might as well retire on their terms right now, or face their citizens in their states and try to defend what they have done," Daines told Fox News Digital in an interview.

GOP ATTACKS VULERABLE 2024 SENATE DEMOCRATS FOR PUTTING MEDICARE, SOCIAL SECURITY ‘AT RISK’

Undecided

Sen. Joe Manchin's, D-Va., seat is considered one of the most vulnerable for a GOP pickup next cycle, as the Democrat weighs another term. 

In 2018, Manchin won re-election by only three points, a state former President Donald Trump won by nearly 40 points in 2020.

Joe Manchin

Sen. Joe Manchin, D-W.V., has not said if he will seek another term in office. (Anna Moneymaker)

Sen. Kyrsten Sinema, I-Ariz., recently stirred it up with the Democrats ahead as she nears the end of her term, leaving the party to register as an independent. While she has not officially announced re-election, Democrats are already pitching her seat.

The Cook Political Report recently dropped Senate ratings for next cycle, revealing the Democrat's majority faces a troubling 2024 election.

CLICK HERE TO GET THE FOX NEWS APP

The election analysis considered three Democratic seats to be "toss-ups" – held by Sen. Kyrsten Sinema, I-Ariz., Sen. Joe Manchin, D-W.Va., and Sen. Sherrod Brown, D-Ohio – all in states that former President Donald Trump won in the 2020 presidential election.